Bluetooth uses a radio technology called frequency-hopping spread spectrum on an unlicensed Industrial, Scientific and Medical (ISM) 2.4 GHz short-range radio frequency band. Bluetooth provides a secure way to connect and exchange information between devices such as faxes, mobile phones, telephones, laptops, personal computers, printers, Global Positioning System (GPS) receivers, digital cameras, and video game consoles. Bluetooth is a communication protocol with a master-slave structure. A master Bluetooth device can communicate with slave devices in a Wireless User Group. This network group is called a piconet. The devices can switch roles, by agreement, and the slave can become the master at any time. The Bluetooth Core Specification allows connecting two or more piconets together to form a scatternet, with some devices acting as a bridge by playing the master role in one piconet and the slave role in another piconet (or slave in both piconets).
Bluetooth low energy (BLE) is based on Bluetooth 4.0 technology, designed with the intention to reduce power consumption of Bluetooth devices. BLE is designed to be applicable to a wide range of applications and devices in the healthcare, fitness, security and home entertainment industries. For example, it is possible for a BLE device to operate several years with a button cell battery without recharging. However, BLE specification has ruled out the possibility for the BLE device to operate in multiple piconets in the above-described manner.